Friday 5 July 2013 12.16 EDT
First published on Friday 5 July 2013 12.16 EDT

England will name a 13-man squad for the first Ashes Test which begins at Trent Bridge on Wednesday with Graham Onions leading the candidates for a call-up. Given that a squad of a dozen only had pretty much been flagged up by who was summoned to Chelmsford – from which it was expected two pace bowlers, Boyd Rankin and Onions, would be discarded – the selectors have therefore added an element of intrigue to something that had appeared straightforward.

In going for the extra man, the selectors insist that it is not for reasons of cover – mindful in particular of the condition of Stuart Broad's right shoulder, which has received a cortisone injection – but to give themselves "options".

The strong implication is that these revolve not around batsmen, with confirmation during the week that only six, those at Chelmsford, would be selected, but around the bowling. And here there are several considerations. Firstly, while Jimmy Anderson and Broad were both rested from the Essex game, neither Tim Bresnan nor Steve Finn, who played in England's last Test, was able to make an overwhelming claim to make the final XI. Nonetheless, both are expected to be included in the squad with a final decision not made probably until the eve of the match.

But the pair were outbowled in the second part of the match by Onions, while Rankin was steady enough. In fact it was Tymal Mills of Essex who caught the eye rather than those on the England side. There could be a case for Onions' inclusion as an option should it be felt that Trent Bridge will produce the degree of swing that is normally associated with the ground, particularly since the construction of the Fox Road Stand that appears to have altered the microclimate. It is the tight line that Onions bowls that has caused problems for Australia in the past as well, particularly when bowling to left-handers who appreciate width. Rankin would seem more superfluous.

Secondly though, the selectors might have taken notice of the positive weather forecast, and a pitch which might well start extremely dry and dust-up from an early stage. In this case, if they anticipated a turning pitch almost from the word go, on which seamers would get little say, then they could turn to a second spinner, probably Monty Panesar.

Under no circumstance will England reduce their batting strength to accommodate a fifth bowler, but in India, they did play with Graeme Swann and Panesar in tandem, with Anderson and Bresnan as the seamers. However, given the fragile nature of Broad's fitness, and the rapid development of Joe Root's off-spin as a credible alternative, the chances of this happening in this country, especially for the first Test of a series, are remote.

The obvious conclusion is that either Onions or Rankin will be retained with a very outside possibility that Chris Tremlett could make a return earlier than had been anticipated. Reports, and his own words, suggest that not only is he back to full fitness but is bowling superbly. England will definitely want him in their touring party this winter, but an earlier appearance would not go amiss. Neither he nor Rankin are thought to be quite ready yet, however. Onions looks certain to join the Trent Bridge ranks.